Fuel inlets for pouring fuel such as gasoline into a fuel tank of a vehicle or the like are conventionally known. Generally, such a fuel inlet (filler pipe) comprises an inlet pipe through which the fuel is introduced from a fuel filler opening to the fuel tank. At a fueling-side end portion of the inlet pipe, a refueling retainer is arranged as a separate body from the inlet pipe.
For example, Patent Document 1 discloses a fuel filler opening structure in which a tubular refueling retainer (a nozzle guide) is provided that guides insertion of a nozzle of a refueling gun. Such a fuel filler opening structure is configured to restrict insertion of the nozzle of the refueling gun by a pair of inward protrusions provided in a recessed manner on the refueling retainer.